code: def test_attribute_assortativity_directed(self):
      r = nx.attribute_assortativity_coefficient(self.D, "fish")
      assert r == 1.0 / 3.0
  
imports: import pytest
  import networkx
  from networkx.algorithms.assortativity.correlation import attribute_ac
  from .base_test import BaseTestAttributeMixing, BaseTestDegreeMixing
label_desc: Use image node_id 2 for calling the TestAttributeMixingCorrelation obj's underlying member method code with example usage: obj.test_attribute_assortativity_directed() without return types